High-speed directional relay element



Nov. 7, 1933. s. L. GOLDSBOROUGH 1,934,664

HIGH SPEED DIRECTIONAL RELAY ELEMENT Original Filed May 1, 1950 WITNESS INVENTOR Shir/69 A. 6020 56 arozxg/z.

4% a/zww ATTORNEY Patented Nov. 7, 1933 UNITED STATES HIGH-SPEED DIRECTIONAL RELAY ELEMENT TQI Shirley L. GoldsborouglnEast Orange, N. J., assignor to Westinghouse Electric & Manufacturing Company, a corporation of Pennsylvania Original application May 1, 1930, Serial No. 448,937. Divided and this application February 1, 1933. Serial No. 654,662

4 Claims.

This application is a division of my application Serial No. 448,937, filed May 1, 1930, for High-speed impedance-responsive relays.

My invention relates to relays and relaying systems particularly designed for use with quickacting circuit-breakers for the purpose of increasing the stability of transmission lines, or the ability of such lines to transmit power without loss of synchronism during fault conditions.

My present invention relates to the directional element of a high-speed impedance-responsive relay which is sold by the Westinghouse Electric and Manufacturing Company as the type HZ relay. It has been developed to solve the problem of a high-speed relay for use in connection with high-speed breakers to effect the rapid clearing of line faults. This relay is capable of operating in 1 cycle or less on a Gil-cycle system. Selectivity is attained by the employment of the impedance principle. This principle has been chosen as it offers the simplest way of obtaining high-speed discrimination.

The principal object of my invention is to provide a very sensitive directional element having a sufficiently high speed of operation to be useful as a part of such a quickly operating impedance relay.

A preferred form of embodiment of my directional element is shown in the drawing, wherein Figure l is a detail sectional view of a part of the directional element, the section plane being indicated by the line I-I in Fig. 2, and

Fig. 2 is a simplified perspective View. of the directional element. 7 I

The apparatus which is commonly sold under the name of a high-speed impedance relay, type HZ, consists of a glass-enclosed box or board having a number of so-called elements mounted thereon or therein.

Each impedance relay is provided with a directional element 24 which is the subject of my present invention. The directional element 24 is preferably of a wattmeter type and in the form shown is provided with a pair of normally closed contacts 26, which are closed at all times :except when current is flowing from the line to be protected, into the bus or station in which the relay is located, in which case there can be no fault in the line which is being protected. The directional wattmeter element 24 is also shown as being provided with a set of normally open contacts 27.

A new type of directional element 24 has been necessitated in order to secure the high speed necessary to enable the directional element of my coil of the directional element.

high-speed impedance-responsive relay to operate such as has been used heretofore, having a rotating disc which is dragged around by eddy-current action, is inherently too slow to be made to op- I erate satisfactorily in a high-speed relay.

It is necessary, in my high-speed relay, to use a directional element operating on the galvanometer principle, by which I mean an instrument having a magnetizable needle or armature which orients itself according to the direction'of the field, or one having a coil through which current is flowing, which reacts with a field to produce movement in the one direction or the other, according to the direction of flow of the current with respect to the field.

As shown in Figs. 1 and 2, my substantially instantaneous directional relay-element 24 comprises two alternating-current windings or coils 63 and 64, the direction of whose currents is to be compared. The winding marked 63 is energized as a voltage coil which is wound as the primary winding of a potential transformer having a closed magnetic core 65, one leg of which is loosely embraced by a .singlefloop 66 of alu- K minum or copper, constituting the secondary winding of the transformer. Current is thus phase with the voltage applied to the voltage The loop 66 is much larger than is necessary merely to embrace a leg of the potential transformer core 65, so as to provide two substantially parallel inductor portions 6'7 and 68 which cooperate with the field produced .by the current winding 64 as follows:

pernic is a magnetic material characterized by having low remanence and a high maximum permeability at low flux densities. It is an alloy of approximately nickel, 50% iron,. and varying quantities of manganese-up to 1%.

The two parallel inductor. sides 6''! and 68 of the loop 66 are disposed in the two air gaps '71 and 72, respectively, so that said sides lie transversely across the flux in said air gaps.

The loop 66 is pivotally supported on an axis parallel to, and substantially midway between, the parallel loop portions 67 and 68 lying in said air gaps 71 and 72, as by means of two bearings 73 and 74. The loop 66 is thus so mounted that it will swing through a small angle when the inductor sides 67 and 68 are displaced transversely in the current-coil field or air gaps 71 and 72 by reason of the reaction between the current in the loop and the flux in the air gap. The loop carries an extending arm 75 which may be of micarta plate, or other insulating material, which rests against a stop 76 in one position of the relay, and which hits against the contactmembers 26 and 27 when the relay rotates a very short distance in the other direction, thereby opening the contacts 26 and closing the contacts 27.

The current and voltage coils 64 and 63 of the directional element are connected to current and voltage sources of such relative phases that the current leads the voltage by 30 degrees when the line power factor is 100%. Thus it follows that, when a fault occurs, the fault current, which is very strongly lagging, will still have a component either in phase with or in phase opposition to the voltage applied to the voltage coil, so that a quick and positive operation will be obtained. This directional element has true wattmeter characteristics and is extremely fast without undue energy consumption.

In its essential features, the directional elemerit comprises a current coil 64 and a coil 63 which is energized by a reference current, with respect to which the phase or direction of the current in the current coil is to be compared. While I have indicated this reference coil 63 as being energized from the line voltage, it is to be understood, of course, that other sources of reference currents which are used for directional relay-elements may obviously be used, but these are not specifically described herein, as they constitute the subject-matter of other applications, such as the application of R. D. Evans et. al., Serial No. 403,390, filed October 30, 1929, and assigned to the Westinghouse Electric and Manufacturing Company; an application of L. N. Crichton et al., Serial No. 437,924, filed March 20, 19 30, and assigned to the Westinghouse Electric and Manufacturing Company; and my application entitled High-speed directional relay element, Serial No. 448,938, filed May 1, 1930.

While I have indicated that the voltage which is applied to the reference coil 63 of the directional element 24 should preferably lag behind the line current by 30 degrees when the power factor of the line is unity, it is to be understood that other angles could be used, if convenient, just so that the short-circuit current of the line, when the power factor is very low, shall not be nearly at right angles to the phase of the voltage applied to the reference coil 63.

In adjusting the directional element, it is desirable that the contacts shall be so adjusted that both sets of contacts are actuated at the same time by the contact arm 75. It is usual to provide about 1/64" clearance between the contacts and the micarta arm 75 when the latter is resting against its stop 76, and to adjust the stationary contacts so that they will have about separationwhen open.

While I have carefully described my new highspeed directional relay element and explained its design and operation in a single preferred form of embodiment, it will be obvious that various changes and modifications may be resorted to without departure from the essential intent and spirit of the invention. I desire, therefore, that the appended claims be accorded the broadest construction consistent with their language and the prior art.

I claim as my invention:

1. A substantially instantaneous directional relay-element of a galvanometer type comprising two alternating-current windings the direction of whose currents is to be compared, one of said windings being wound as the primary winding of a magnetic-core transformer the secondary winding of which consists of a single loop loosely embracing one leg of the core, the other of said windings being Wound as the stator of a galvanometer having two air gaps across which its flux is passed, two substantially parallel sides of said loop lying transversely across said flux in said air gaps, and means for pivotally supporting said loop on an axis substantially parallel to, and substantially midway between, the substantially parallel loop portions lying in said air gaps.

2. A substantially instantaneous directional relay-element of a galvanometer type comprising two alternating-current windings the direction of whose currents is to be compared, one of said windings being wound as the primary winding of a magnetic-core transformer the secondary winding of which consists of a single loop loosely embracing one leg of the core, the other of said windings being wound as the stator of a galvanometer having an air gap across which its flux is passed, one side of said loop lying transversely across the flux in said air gap, and means for pivotally supporting the loop on an axis substantially parallel to said loop-side lying in said air gap.

3. A substantially instantaneous directional rclay-element of a galvanometer type comprising two sources oi. alternating-current fluxes whose direction is to be compared, one of said sources being applied to a magnetic-core transformer the secondary winding of which consists of a single loop loosely embracing one leg of the core, the other of said sources being applied to the stator of a galvancmeter having two air gaps across which its flux is passed, two substantially parallel sides of said loop lying transversely across said flux in said air gaps, and means for pivotally supporting said loop on an axis substantially parallel to, and substantially midway between, the

substantially parallel loop portions lying in said air gaps.

4. A substantially instantaneous directional relay-element of a galvanometer type comprising two sources of alternating-current fluxes whose direction is to be compared, one of said sources being applied to a magnetic-core transformer the secondary winding of which consists of a single loop loosely embracing one leg of the core, the other of said sources being applied to the stator of agalvanometer having an air gap across which its flux is passed, one side of said loop lying transversely across the flux in said air gap, and means for pivotally supporting the loop on an axis substantially parallel to said loop-side lying in said air gap.

SHIRLEY L. GOLDSBOROUGH. 

